Tray, particularly for foodstuffs

ABSTRACT

The inventive tray includes a bottom (2) and four side walls (3-6), which have an extension in the form of a folded-out edge flange (11) in a plane parallel to the bottom (2) of the tray (1) and forming a continuous frame for coaction with a separate lid, sealable to the tray (1). At their upper portion (9) the side walls (3-6) are inclined inwards so that the continuous frame formed by the edge flange (11) is substantially within the outer contour of the side walls (3-6).

The present invention relates to a tray, particularly for foodstuffs,said tray being produced from a stamped and creased blank made fromcarton or the like stiff material, said tray consisting of a bottom andfour side walls, the latter being connected to each other in pairs by acorner structure consisting of at least two substantially triangularareas in contact with adjacent side walls having extensions in the formof folded-out flanges, which lie in a plane parallel to the bottom ofthe tray and form a continuous frame for coaction with a separate lidwith which the tray may be closed.

Trays of this type are used for foodstuffs, and then often forready-cooked food, which is usually warmed up directly in the tray, e.g.with the aid of a microwave oven or a hot air oven. In the known traysthe side walls are provided with folded-out, outstanding edge flangesforming a frame against which a lid is intended to be fixed, e.g. byhot-melt sealing, after the tray has been filled. During the packing ofthese trays the outstanding edge flanges have caused quite a fewproblems. From the handling aspect, the flanges result in that the trayscannot be put on their side edges during packing, and that hookingtogether or flange collisions occur, with the result that there is trayleakage. Furthermore, the flanges take up space, since a gapcorresponding to the flange width occurs between the trays when they arepacked side by side.

The drawbacks of this known type of tray have been eliminated by theinvention, which proposes the provision of a tray of the kind mentionedin the introduction, which can be stacked both side by side and on aside edge during packing without any outstanding flanges catching ineach other or forming air gaps between the trays. Essentiallydistinguishing for the invention is that each of the side walls isinclined at an acute angle to the bottom plane of the tray in the areaabove a crease line extending round the periphery of the tray and at agiven distance from the bottom plane thereof, so that the continuousframe formed by the edge flanges is substantially inside the outercontour of the side walls. There is accordingly provided a tray, which,in spite of its being provided with an edge flange running round itsopening, for coaction with a lid tightly sealing the tray, does not haveany parts projecting outside the contour of the side walls.

The invention will now be described below with reference to someembodiments illustrated by way of example on the appended drawings.

FIG. 1 is a perspective view of a first embodiment of a tray inaccordance with the invention,

FIG. 2 is an end view of the tray illustrated in FIG. 1,

FIG. 3 is a plan view of the blank to the tray illustrated in FIGS. 1and 2,

FIG. 4 is a perspective view of a second embodiment of the tray inaccordance with the invention, in which the fastening flaps are fixed tothe inside of the short side walls,

FIG. 5 is an end view of the tray illustrated in FIG. 4,

FIG. 6 is a plan view of the blank to the tray illustrated in FIGS. 4and 5,

FIG. 7 is a side view of a third embodiment of the tray in accordancewith the invention and

FIG. 8 is a plan view of the blank to the tray illustrated in FIG. 7.

The tray 1 illustrated on the drawings is preferably manufactured fromcarton or the like stiff material, having at least on the side facingtowards its interior a liquid-proof, sealable, hightemperature-resistant coating such as polyester. The tray 1 has a bottom2 and four side walls 3, 4, 5, 6 connected in pairs to each other by acorner structure 7 including a fastening flap 8, which is eitherattached to the outside or inside of the adjacent side wall. The sidewalls 3, 4, 5, 6 have an upper portion 9 inclining at an acute angle tothe bottom 2 of the tray 1 from a crease line 10 round the tray 1. Theside walls 3, 4, 5, 6 have an extension in the form of an edge flange11, folded out in a plane parallel to the bottom of the tray 1 from theupper inclined portion 9, and forming a frame running round the openingof the tray 1 for coaction with a separate lid which is sealable againstthe tray 1, although this lid is not shown on the drawing. The upperside wall portion 9 forms an angle to the bottom 2 and extends upwards adistance there from such that the continuous frame formed by the edgeflange 11 is inside the outer contour of the side walls 3, 4, 5, 6.

With the aid of crease lines 12, 13, 14, 15 the blank depicted on thedrawings is divided into a bottom 2 and four side walls 3, 4, 5, 6. Theends of the sides merge into a corner structure or portion 7 which formstwo triangular corner areas 18, 19 with the aid of two outer creaselines 16, 17, the two triangular areas being divided by a crease line20. All these corner crease lines 16, 17, 20 start from the respectivecorner 21 of the bottom 2. An extension running substantially round thewhole of the periphery of the blank forms the edge flange 11 when theblank is erected. This edge flange 11 is defined by an edge crease line22, between which and the crease lines 12-15 there extends a crease line10 substantially round the whole of the blank at a predetermineddistance from the bottom crease lines 12-15. At its free outer end oneof the two outer corner crease lines 16, 17 has two converging creaselines 24, 25 which meet each other at a point 23 situated on the edgecrease line 22. The outer crease line 24 starts from the end 26 of thecorner crease line 16 at the periphery of the edge flange 11, and theother crease line 25 starts from the intersection point 27 of the cornercrease line 16 with the crease line 10. These crease lines 24, 25 arepreferably situated on one of the triangular areas 18 or 19 forming thecorner portions 7. It is possible, however, to extend the crease lines24, 25 on the outer portions of the side walls outside the crease line10. Either of the corner areas 18 or 19 in the corner portion 7 has anextension in the form of an edge flange, similar to the side walls,which may be folded out along an edge crease line 28 when the blank iserected, and constitutes an extension of the edge crease line 22 of theadjacent side wall.

The blank illustrated in FIG. 3 has a corner structure 7 in which thefastening flap 8 is intended to be attached to the outside of the sidewalls 3, 4 when the blank is erected, as will be seen from the erectedblank 1 illustrated in FIGS. 1 and 2. Of the two outer corner creaselines 16, 17 defining the corner areas 18, 19 in this embodiment, one 16of them forms a normal to the bottom crease line 13, 15 of the adjacentside wall 4, 6, while the other corner crease line forms an acute angleto the bottom crease line 12, 14 of the adjacent side wall 3, 5. Thecorner area 19 has a cutout 29 contiguous to the corner crease line 17via a flap portion 30. The flap portion 30 is divided by a short creaseline 31 into an inner 32' and an outer part 32. During a first operationin the erection of the blank illustrated in FIG. 3, the side walls 3, 6are folded up, by an unillustrated forming tool including outer andinner erecting means, to a position in which the fastening flaps 8,achieved by double-folding of the areas 18, 19 along the crease line 20,are attached preferably by heating to the outside of the side walls 3,5. In a second operation subsequent thereto, unillustrated outer andinner forming means move diagonally inwards, at least towards the cornerportions 7 of the tray 1, for providing an inward positionaldisplacement of the edge flange 11 and the upper portion 9 of the tray 1round the side walls 3-6 of the tray 1 and parallel to the crease line10 running round the bottom 2, simultaneously as the edge flanges 11 arefolded out to a position parallel to the bottom 2, and the cornerportion 7 under the edge flange 11 is rolled in and the excess materialthere compressed into the space 33 arranged in the corner portions. Thisspace 33 occurs in this embodiment between the corners 34 of the erectedblank and a crease band 35 formed by the corner crease line 17.Pressing-in of the corner portion 7, whereat the sloping upper portion 9is formed, is facilitated by the presence of the crease lines 24 and 25extending over the upper portion 9 and the edge flange 11. During thefirst erection operation, the tray blank can be supplied with sufficientheat so that forming during the second operation can be carried out witha cold tool. The tray corners will be extremely well sealed by thepresence of the flap portion 30, through with the aid of which theplastics coated side of the blank is in contact (plastics to plastics)from the bottom corner 21 right out to the periphery of the edge flange11 after the blank has been erected. Direct contact between two edgeflange layers situated one on top of the other is provided by the cutout29, except at the outer portion 32 of the flap portion 30.

The blank illustrated in FIG. 6 has a corner structure 7, in which thefastening flap 8 is intended for attachment to the inside of the sidewalls 3, 5 when the blank is erected. This may be suitable from thedecoration aspect, for example. A tray 1 manufactured from the blankillustrated in FIG. 6 is shown in FIGS. 4 and 5. In this embodiment bothcorner crease lines 16, 17 form a right angle to the bottom crease lineof the contiguous side wall. Similar to the first embodiment describedabove, the corner area 18 is provided with an edge flange and bothcrease lines 24, 25, while the other corner area 19 is provided with atriangular cutout 34. This cutout 34 has one of its corners at themeeting point 35 of the corner crease line 17 and the crease line 10,and has its side edges 36, 37 extending to the outer edge of the cornerarea 19, said outer edge being defined by an imaginary linear extensionof the edge crease line 22 of the contiguous side wall 3, 5. Erection ofthe blank illustrated in FIG. 6 is accomplished in the same way as thatfor the embodiment described above and illustrated in FIGS. 1-3, exceptfor the folding of the fastening flaps 8, these flaps being attached tothe inside of the tray side walls 3, 5 for the blank illustrated in FIG.6. When the blank is erected, the cutout 34 provides a space 38 belowthe edge crease line 22 to enable pressing in the corner portion 7 underthe edge flange 11.

The blank shown in FIG. 8 has a corner structure 7 in which thefastening flap is intended to be attached to the inside of the sidewalls 3, 5, similar to the case with the embodiment illustrated in FIGS.4-6. The corner structure 7 for the embodiment using the blankillustrated in FIG. 8 is however designed so that the erected blankforms a tray 1 with conical side walls 3-6 i.e. these form an obtuseangle to the bottom 2 of the tray 1. This tray variant makes thecontents of the tray 1 easily available, in spite of waisting the upperportion of the tray. The difference between this embodiment and the oneillustrated in FIGS. 4-6 is only that the outer corner crease lines 16,17 form an angle which is greater than 90° to the bottom crease lines12-15 of the contiguous side walls 3-6, and that the crease lines 10, 28on the corner areas 18, 19 must have a somewhat different extension,although the corner crease line 20, will be the same, as a result of theinclination of the crease lines 16, 17, when the blank is in a flatcondition, for these crease lines 10, 28 to coincide with the side wallcrease lines 10, 22 when the blank is erected.

I claim:
 1. A tray produced from a stamped and creased blank made fromcarton or the like stiff material, said tray (1) consisting of a bottom(2) and four side walls (3-6), the latter being connected in pairs toeach other by a corner structure (7) consisting of at least twosubstantially triangular areas (18, 19) in contact with adjacent sidewalls (3-6) having extensions in the form of folded-out flanges (11),lying in a plane parallel to the bottom (2) of the tray (1) and forminga continuous frame, for coaction with a separate lid with which the traymay be closed, characterized in that each of the side walls (3-6)consists of a lower and an upper wall portion, the former being foldedup along a crease line (12-15) defining a bottom (2) such that it issubstantially perpendicular to the bottom plane of the tray (1) and hasa height from the bottom (2) attaining to at least half the tray height,said lower wall portion merging into the upper wall portion along acrease line (10) extending round the periphery of the tray (1) at apredetermined distance from the bottom crease line (12-15), said upperwall portion inclining at an acute angle to the bottom plane of the tray(1) and extending towards the interior of the tray (1) a distancesubstantially corresponding to the width of the continuous frame formedby the edge flanges (11), said frame being situated substantially withinthe outer contour of the bottom (2).
 2. Blank for a tray (1) having abottom (2) and side walls folded up along creased lines (12-15) definingsaid bottom (2), said side walls being inclined at an acute angle to thebottom of the tray (3-6) being provided at their upper edges withoutwardly folded edge flanges (11) forming a continuous frame, saidcontinuous frame lying substantially within the outer contours of saidside walls, at each corner portion (7) the blank having three cornercrease lines (16, 17, 20) starting from the respective bottom corner(21) and defining two substantially equal and triangular areas (18, 19),for double folding along their mutual crease line (20) to form asubstantially triangular double-walled fastening flap (8) intended forattaching to one of the adjacent side walls (3, 5), subsequent to whichthe edge flanges (11) may be folded out along edge crease lines (22),and a crease line (10) is situated between the bottom crease lines(12-15) and the edge crease lines (22), and extends along the side walls(3-6) at a predetermined distance from, and parallel to, the bottomcrease lines (12-15) substantially round the whole blank.
 3. Blank asclaimed in claim 2, characterized in that there are two convergingcrease lines (24, 25) for facilitating pressing in the corner portion(7) under the edge flange (11) and folding out the edge flange (11) whenthe blank is erected, one of said lines (24) starting from thetermination point of the crease line (16) at the outer edge of saidflange (11) and meeting the line (25) at the crease line (28), wherefromthe line (25) extends, to terminate at the intersection of crease lines(16 and 10).
 4. Blank as claimed in claim 3, characterized in that thecrease lines (24, 25) are situated on one of the triangular areas (18,19) of the corner portions, said area (18) including an edge flangeconstituting a continuation of the edge flange (11) of the contiguousside wall, said extension being defined by the outer corner crease line(16) and edge crease line (28).
 5. Blank as claimed in claim 3,characterized in that one (16) of both outer corner crease lines (16,17) forms a normal to the bottom crease line (13, 15) of the contiguousside wall (4, 6) and that the other (17) outer corner crease line formsan acute angle to the bottom crease line (12, 14) of the contiguous sidewall (3, 5), whereby a space (33) at the upper portion of the cornerstructure (7) occurs after attaching the fastening flap (8) to theoutside of said side wall (3, 5) between the corner (34) of the erectedblank and the crease bead (35) formed by the other outer corner creaseline (17) to allow the inward urging of the edge flange (11) andpressing in the corner portion (7) under the edge flange (11).
 6. Blankas claimed in claim 5, characterized in that the corner area (19)defined by the crease line (20) and the other, outer corner crease line(17) has a cutout (29) at its outer edge contiguous to said cornercrease line (17) via a flap portion (30), direct contact between twoedge flange layers situated one on top of the other being obtained afterthe blank has been erected, excepting at a portion (32) of the flapportion (30) at the free end of the outer corner crease line (17). 7.Blank as claimed in any of the preceding claims, characterized in thatone outer corner crease line (17) in the respective corner structureterminates at the intersection point (35) with a crease line (10)situated between the bottom crease line (12-15) and the edge crease line(22), from said intersection point (35) there beginning a triangularcutout (34) with its apex situated in said intersection point (35) andits side edges (36, 37) extending to the periphery of the corner area(19), whereby a space (38) is created below the edge crease line (22)when the blank is erected, for enabling pressing the corner portion (7)under the edge flange (11).
 8. Blank as claimed in any of the claims1-6, characterized in that the outer corner crease lines (16, 17) forman acute angle to the bottom crease line (12-15) of contiguous sidewalls (3-6), whereby the side walls mutually diverge from the bottom (2)of the tray (1) after the blank is erected.